Extreme beginner question

[Sensor]

I have a very basic question here regarding the INPUT function. I am playing with a PIC Microcontroler and trying to make it respond to buttons. In the process I learned that I need to have a debouncer for the buttons, since the pressing of a button is registered more than once on a single push.
Since I have multiple buttons, I would like to write a simple little function that will take as input the button pushed and debounce it.
Following is the code I am currently using:
void debounce(int bt)
{
delay_ms(250);
while(!input (bt))
delay_ms(20);
}
The message I get is:
Expression must evaluate to a constant.

Every example I saw sofar is not telling me how to pass a variable to a function like INPUT. They usually pass #DEFINEs i.e.
input (PIN_A1)

Is it possible to pass a variable to input?

thanx
Iggy

[SherpaDoug]

The function input() needs something it can evaluate at compile time, not a variable. There are complex ways to get around this by reading the input as a memory location through a pointer. But I would first ask if all your buttons are on the same port? Then you can just read the port into a byte and address the individual buttons a bits within the byte. Bit_test() may have the same problem, I don't remember but you can find out quickly enough. If Bit_test() won't take a variable you can always shift the byte till you get the bit you want. More efficient would be a union of a byte for the port with a struct of boolians, but that might be confusing for a raw beginner. It is OK if there are other things on other pins of the port for you to ignore.

Happy exploring!
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